Drivers who frequently use cell phones behind the wheel have more near-misses and crashes than other drivers, according to newly published research, but this trend "seems to have little or no effect on overall crash/near-crash risk." 

The Insurance Institute for Highway Safety (IIHS) and Virginia Tech Transportation Institute (VTTI) released two new studies examining the impact of driver cell phone use – and some of their conclusions buck conventional wisdom about distracted driving. Study authors indicated their findings suggest the need for further research into whether driver phone use adds to or replaces other distracting activities.

"Some of the increased risk while interacting with the phone may be mitigated by compensatory driver actions," one study said. For example, drivers tend to slow down when dialing the phone. Additionally, researchers concluded that drivers not using a phone tended to engage more in other distracting behavior, such as talking with passengers, eating, drinking and smoking.

Researchers analyzed data VTTI previously collected for a naturalistic driving study conducted in 2003-2004 for the National Highway Traffic Safety Administration (NHTSA). The age of the data alone has raised questions about the merits of the research.

The National Safety Council released a statement challenging the validity of some of the studies’ conclusions, pointing out that they are based on data about a decade old – before the advent of smartphones. Additionally, NSC said that cell phone use in crashes is "significantly underreported – drivers don't often admit to cell phone use, and it's often not captured on crash reports."

"Studies that are based on limited data and underreported statistics produce findings that are incomplete and misleading,” NSC said.

NSC estimates that driver distraction tied to cell phone use is a factor in 26 percent of all crashes.

One of newly released studies from IIHS and VTTI examines the relationship between driver cell phone use and the risk of a crash or near-miss, while the other study delves into whether driver cell phone use affects the frequency of other distracting behavior.

“Although cell phone use can be distracting and crashes have occurred during this distraction, overall crash rates appear unaffected by changes in the rate of cell phone use,” the crash risk study concludes. “Drivers compensate somewhat for the distraction by conducting some of the more demanding tasks, such as reaching for or dialing a cell phone, at lower speeds. It is also possible that cell phones and other electronic devices in cars are changing how drivers manage their attention to various tasks and/or changing the kinds of secondary tasks in which they engage.”

The data were culled from the day-to-day driving behavior of 105 volunteers. To classify driver behavior, researchers watched in-vehicle video. They estimated the proportion of driving time spent using a cell phone for three-month periods and then correlated that with overall crash and near-crash rates for each period.

Drivers in this study spent 11.7 percent of their time interacting with a cell phone, mostly talking (6.5 percent) or simply holding the phone in their hand or lap (3.7 percent). The risk of a near-crash or crash was about 17 percent higher during such interaction with a phone.

When drivers reached for the phone, answered it or dialed it, their crash risk level was nearly triple that of fully attentive drivers. Nonetheless, overall crash rates appeared unaffected by changes in the rate of cell phone use, according to researchers.

Data also indicated that drivers slowed down for calls. Vehicle speeds within six seconds of the beginning of each call, on average, were 5-6 mph lower than speeds at other times, the study notes.

Anticipating the controversy, IIHS released an essay by IIHS President Adrian Lund titled, “The Self-Correcting Nature of Science,” along with a status report stressing that “the research points to the need for a broader strategy to deal with the ways that drivers can be distracted.”

The lead author of both studies, Charles Farmer, underscored the need for further study.

“Using phones while driving raises a driver’s risk of having a crash because it takes attention away from the road,” Farmer said. “Although there have been tragic cases of fatal crashes caused by drivers using electronic devices, an effect on overall crash rates isn’t apparent. The research is still unfolding, but there is a basic conundrum: Why is a distracting behavior not increasing crash rates?”

The Lund-penned essay acknowledges that back in July of 2005, IIHS released a report warning that the more time a driver spends on the phone, the greater the crash risk. But the new findings shed more light on the complicated issue of distracted driving, he said.

“Our new research with VTTI confirms that a driver not using a cell phone is not necessarily more engaged with the driving task but, rather, may engage in other actions – intentionally or unintentionally – that take his or her attention off the road to the same or even greater extent,” Lund wrote. “Future research will continue to correct our understanding and treatment of distracted driving. This is how science works.”

Both IIHS and NSC clearly agree, however, that the battle against distracted driving can’t focus solely on cell phone use.

In the study examining whether driver cell phone use affects the frequency of other distracting behavior, researchers found that drivers spent 42 percent of their time involved in at least one secondary activity. Drivers talked on a cell phone 7 percent of the time, interacted in some other way with a cell phone 5 percent of the time, and engaged in a different activity – sometimes while also using a cell phone – 33 percent of the time.

In general, when drivers spent more time talking on a cell phone, they spent less time on other distracting behavior, the study says.

“Although using a cell phone can be distracting from the driving task, other secondary activities can be equally or more distracting, at least as measured by eye glances away from the road ahead and mirrors,” the study notes.

To learn more about both IIHS-VTTI studies, click here.

To read the statement from the National Safety Council, click here.